Miss Ethel Tither has made herself deeply unpopular in the quintessentially English village of Hilary Magna, since she goes out of her way to snoop on people, and interfere with their lives. She is found floating in a cesspool, having been bludgeoned prior to drowning in the drainage water. This is, in every way, a murky business; realising that they are out of their depth, the local police quickly call in the Yard. Inspector Thomas Littlejohn arrives on the train, and in casting around for suspects, he finds that he is spoiled for choice. But he must piece together the clues to discover who was responsible for the death of the busybody.